Pneumatic hammer.



Patented Aug'. 18, 19M

3 SHEETS SHFE'JL Q11 mudo@ eorqe l.: Rabersan,

G. l. ROBERTSON. PNEUMAIIG HAMMER. APPMUANUN FILED APR. 1n. 1914.

Patented Aug. 18, 1914.

3 SHBBTBBHBET 2.

L e w GEORGE LAWSON ROBERTSON, 0F PHILADELPHIA,

PENNSYLVANIA.

PNEUMATIC HALIMER.

Application led April Specification of Letters Patent.

Patented Aug. 18, '1914.

15, 1914. Serial N0. 832,020.

To all whom it may concern.'

Be it. known that I, GEORGE LAwsoN oen'n'rson, a citizen of the United States, residingr -at Philadelphia, in the county of 'hiladelphia and State of Pennsylvania,

ave invented certain new and useful Im- 'provements in lneumatic Hammers, of which the following is a specification.

My invention relates to improvements in pneumatic hammers, an object of the invention being to provide a pneumatic hammer withfan improved construction of valve coperating with anf improved arrangement vof ports and .passages in the hammer to control the movement of the piston.

A further object is to provide in the barrel, a longitudinally movable shank-supporting bushing, the movement of which, by pressure of the tool against a rivet, automatically admits Huid to the hammer, and `when pressure on the tool is relieved, the bushing-is caused to moveto stop-the operation of the hammer.

A further object is to provide an improved pneumatic hammer in which accidental displacement of the working tool and piston is prevented.

A further object is to provide a pneumatic hammer in valve in the 'handle is dispensed with, and which is caused to operate, and to cease operation in accordance with'V the pressure of the tool in the barrel against a rivet or other object.

A further object is roved two-part valve, both parts movable and moved byfluid pressure to control the passage of luid, so that the operation is entirely automatic.

With these and other objects in view, the invention consists in certain 1novel features of construct-ion and' combinations and arrangements of parts, as will be more fully hereinafter described and pointed o-ut in the claims.

to provide an im- In the accompanying drawings: Figure 1` is a view in longitudinal'section illustrating' normal operativefpo# my improvements in sition with the piston'hmoving forw rdly. Fig. 2 is an enlarged' view in side elevation of the inner valve section. Fig. 3 is a similar view of the outer" valve section. Fig. 4: is a fragmentary view in ongitudinal sec; larged scale showing the potion on an en sit-ion of the valve during the return stroke which the ordinary throttle of the piston. section on the line Fig. 5 is a view in cross 5-5 of Fig. l. Fig, 1s a view in cross section on the line G-6 of Fig. 4. F ig. T is a view similar to Fig. l showing the hammer in its inoperative position. f Fig. 8 is a view in cross section on the line Sf-S of Fig. 4, and Fig. 9 is a v fragmentary end elevation of the handle 'Y handle, this disk is ldraw the pins 17 out segmental grooves 19 whichhold the illustrating a portion of the for the handle.

barrel of my improved pneumatic hammer, having at its rear edge, an enlarged casing` 2 in which a valve box 3 is secured. This valve box is, for convenience of manufacture, formed of a plurality of sections having fixed relationship nto each other and secured together in any approved manner.

I have illustrated dowel pins 4 engaging in the barrel to prevent rotary movement of the box. rThe rear end of the box is closed by a head 5 which has a pin 6 at its periphery engaging in a recess 7 in the casing 2 of barrel 1 to prevent any rotary movement of the head, so that the several ports hereinafter referred to are maintained in alinement. The rear casing end of the barrel is externally screw-threaded as shown at 8 to receive the integral internally screwthreaded cap 9 on the handle l0. To lock this handle against r'- cidental movement, I provide'an angular socket 1l in the head 5, which is located in register with a cylindriral socket 1Q in the cap 9.

lll is a rod which extends opening in the end of the cap, and 1s provided on its outer end with a disk 14. A nut 15 is fixed to the inner end of the rod 13, `and its angular portion is held in the socket ll by means of a coiled spring` 1G. The. disk yll has inwardly"projecting pins 17 which are normally positioned in sockets ltlwand hold the parts against movement. When, however, it is desired to release the drawn outwardly to of the sockets 1S, when be turned, the pins` moving: in disk in a position to contract the spring and hold the locking nut out of engagement with the head. The handle can then.-be unscrewed and replaced as will be understood.

In the valve box 3, myimprove `twoart valve is located, and consists of an inner section 2O and an outer section 21,

socket or cap, locking mechanism l. represents the thro ugh an the disk can both of general cylindrical forni with the Hotel' sertion mounted to telescope on the inner sfwtifm and the inner section located salutv in advance ol' the outer section as clearly in Fig. 4. The inner valve srrtiou Lfl is provided with four annular lianges 22, 23. 24, and the flanges 2l and Q5 being smaller in diameter than the flanges :"2 and 9?, and said flanges 24 and 25 fitting within the outer valve section 21. It will be noted that the thickness of the Wall of valve section 2l is just sufficient to bring the outer sur aice of said outer section Hush with. the outer surfarcs of langes 23 and 2A.

lt is iv te undersztoml that the valve see.- tions are to be inarloof extremely thin metal. so that they will be relatively light and quickly respond to the action of the pressure fluid. and I ha ve necessarily exaggerated the thickness of metal for clcarness of il lustration. The outer valve section is provided at its rear end with an annular enlargement 2G, and at its extreme rear end has a cylindrical portion 27 Which fits a rvlindrieal block 28 on the head 5, and moves longitudinally of the barrel, but always upon thc block for a purpose which will hereinafter appear. The two valve sections have each certain pressure surfaces of different relative areas, and for convenience of description, I shall give each of these pressure surfaces a separate reference character.

The forward face of the flange 22 constitutes a relatively large pressure surface 29 at the forward end of inner valve section 20. The rear face of flange 25 constitutes a pressure surface 30. slightly smaller than the pressure surface 29. he rearface of the enlargement 26 constitutes a pressure surface 3l which is relatively large as shown. The forward face of the enlargement 26 constitutes a relatively small pressure surface T-l, and while both of these surfaces 31 and T4 are on the same enlargement, the difference in the diameter of the forward and rear end of said outer section compensates for the different areas ofthe pressure surfaces. The other surfaces of the", valves are for purposes of cutting off passages and directing the flow of fluid as Will be hereinafter pointed out.

In the forward end of the barrel 1, I provide a longitudinally movable bushing 32 to receive the shank 33 of the tool 34, an ordinary guard 35 being illustrated to hold the tool in the barrel. The bushing 32 is of two external diameters. Its larger diameter, which is at its forward end, is provided with a key 36 which moves in a longitudinal groove 37 in the inner face of the barrel so as to limit the movement of the hashing.n To position the key in this groove-fthe bar rel is provided with an internal annular groove 38 which communicates with a groove and it will be noted that 39, extending to the end of the ba'rrel so that the bushing can be inserted with the key in groove 3S) until the annular groove 3S is reached. The bushing is then given a partial rotary movement until the l-:cy registers with groove 36, when the luishing can be moved within the contines of the groove Without danger of falling out of the barrel.

The barrel is formed with an annular recess 40, which accommodates the larger dia meter of the bushing, and in the inner end of this recess,y I locate a. coiled spring 41 which bears against a shoulder 42 on the bushing l'and tends always to press the bush inf; in a foiirard dirertioii. it being understood that the smaller diameter of the bushing lits within tlnl bore i3 of the barrel, and holds the shank 33 of the tool in position to be engaged by the reciprocating piston 44. The handle 10 is provided with an inlet passage 45 for the motive fluid which enters an annular chamber 46 in the cap 9 and then flows through a circular series oi longitudinal passages 47, there being ten of these passages 47 illustrated. I would have it understood that I do not limit myself to the number of these or other passages hereinafter referred to. but in order that I may set forth an .arrangement which I believe to be a preferable one. I shall define the number of such passages which are stated proportionately rather than with 'a view to any definiteness of number.

Assuming the parts to be in normal working position, with the piston moving forwardly as shown in Fig. 1, the passages 47 communicate With radial ports 48 in the enlargement 26 of outer valve section 21. These ports 4S register `with an. annular groove i9 in the valve box 3, said groove being located approximately midway between the ends of the passages 47. hence when in the position stated. the live fluid has free access to the interior of the valve section 2l, said valve section, Where it is provided with the ports 18, has an internal annular groove 50 for the better distribution of live fluid entering the saine. IVhen in this position1 the inner valve section 2O is located in its extreme forward position. so that its rear end registers with the forward wall of groove 50, and the live fluid flows through the valve section 20 and exerts pressure against the rear end of piston 44 driving the latter forwardly. The fluid in advance of the piston is forced out through a series of longitudinal passages 51, preferably live, which communicate at their rear endnvith exhaust passages 52 which discharge forwardly and against a protecting ring 53 as shovn. W'hen the piston 44 almost reaches the shank 33 of the tool, it will unc/over the end of a passage 54 which directs the live fluid against the forward pressure surface 29 of inner valve section 20.

Immediately the inner valve section is caused to move rearwardly and assumes the position shown in Fig. 4. The blow of the piston against the tool shank, causes a rebound of the piston' which is almost sullicient to return it to the rear of the barrel, and hence very little fluid is necessary to cause this return.` During the return movement of the piston, the live fluid in passages 47 flowsthrough the forward ends of said passages into an annular chamber 55, and thencethrough openings 5G and 57 in the outer valve section, the fluid in its 'passage being directed from one opening to the other by reason of the fact that an annular chamber 58 is 'formed between the flanges 24 and 25 of the inner valve section. The openings 57 communicate with an internal annular groove 59 in the valve box 3, and said groove communicates with the rear ends of the passages 51, so that while a portion of this live fluid will escape through the exhaust passages 52, a sufficient amount will flow forwardly through the passages 51 to insure a complete return of the piston to the rear end of the barrel. The fluid in front of the piston exhausts freely through a circular series of openings 60 in the inner valve section 20 into an internal annular groove 61 in the valve box, the latter being provided with a series of exhaust ports 62. The groove 61 also communicates by radial passages 63 with the exhaust ports 52, so that there is a free exhaust during the return movement of the piston. During the rearward movement of the piston, this fluid in front of the piston exerts a pressure through passage 54 againstv the pressure surface 29 until such passage is closed by the piston. To supply pressure on this surface, during the rest of the rearward movement of the piston, sufficient to prevent the valve from accidentally shifting, I provide a radial port 64 in a longitudinal passage 65. The passage 65 communicates at its rear end with the annular chamber 46, so that it is always supplied with live fluid. The radial port 64 communicates with an annular groove 66 in the box 3, so that a sufficient amount of livefluid is admitted against the pressure surface 29 when the section 20 is in its rearward position. Yhen, however, the section 20 is in its forward position. this groove 66 is cut off' by the Harige 22. The inner valve section, near its rear end, is provided with a, circular series of openings 6T which communicate with a space 68 formed between. the rear pressure surface 30 of the inner valve section, and an annular surface 69 on the outer valve section. This pressure surface 30 is slightly smaller than the pressure surface 29, and the movement of the pressure fluid in front of' the piston is not suflicienthto shiftthe :valve until the piston reaches the extreme of its rearward movement. It `will be ntedthat the inner valve section 20 is of slightly greater internal diameter from a point 70 to its rear end. This is shown on an exaggerated scale on the drawing. It is extremely slight in actual construction. The purpose of this is to overcome a severe fluid pocket between the piston 44 and the head 5, but tlnarearward movement of the piston will create a sufficient pressure to overcome the pressure on surface 39 and exert a greater pressure on surface 3() to cause the valve section 20 to move forwardly to its position above described. The access of pressure between the piston and the head will be enough to accomplish this purpose, but to prevent any possibility of too great a presure, and hence a shortening of the movement of the piston, the difference in internal diameter is provided, such excessive fluid escaping through the openings 6U info the exhaust passages.

The longitudinal passage 65 above rcferredto extends to the forward end of" the barrel, where it is normally cut off' by the larger diameter of the bushing as shown clearly in Fig. 1. lVhen, however, the bushing is moved forwardly by the action of spring 41, after the pressure on the tool is relieved, the air in this passage 65 will flow around the recess 40 and into a longitudinal passage 71 which extends to the rear of the barrel and exerts pressure against the pressure surface 31 of' the outer valve section 21, causing this outer valve section to move forwardly to the position shown in Fig. 7. and when in such position, entirely cut off the inlet of live fluid to the hammer. lhen the bushing is moved rearwardly by reason of a pressure of the tool against a rivet, the flow of fluid through passage 65 will be cut oli' and the end of passage T1 will be connected with the groove 39 in the barrel by means of a longitudinal groove 72 in the outside of the bushing,`so that the pressure surface 31 is exposed to the atmosphere, and does not resist the movement of the valve section. As soon as this takes place, `the pressure of live fluid from the forward ends of the passages 47 against the extrenwly small pressure surface 74, at the forward portion of the. enlargement 26 of outer valve section 21, compels the outer valve section to move rearwardly so as to admit fluid to the hammer and permit the operation as above described. V

The operation is as follows: Fig. 7 shows the hammer in its locked inoperative position in which it will -be observed that the live fluid in, passage 65 assists the spring 41 in exerting a pressure on the shoulder 42 to maintain the bushing in its forward position, and as above explained when in this position, the live fluid passes through passage 71, and exerts pressure upon the surface 3l to cut off the entrance nflivc iuid to the other pau" of the hammer. When the tool 34 is p; Ved against a rivet, the bushing` 32 ivill'a: moved rearwardlv. rlhe first operation ol this rearward naw-eA nient will be to out oil' passage 1li. so that it is only necessary to overcome the prefsure o f the spring` to hold the device in operative position. Furthermore, this rear-- Ward movement of the bushing opens the outlet end of passage 7l at the forward end of the hammer, so that there is -no pressure now against the surface Yi Instantly; tho

live fluid iu the 'passano l? oxf'ris a roar-- Ward pressure airain; ,variare Elli. causing the outer sortira to 'more liv. and heure the several portsl and p.V will he in vommuilimtion as shown in Vig'. L it is not necessary to again deseriae fluid in its movement of lhe pistou. exeepl' to say that the operation of shifting the valve is entirely automatic, and during the normal operation, the outer section 21 remains stationary, While the inner section 20 is moved longitudinally. The forward movement of the inner section 2l is limited by the engagement of surface Q9 with the valve hex 3, and the rearward movement of this inner section is limited by the flange 2B enefaging the forward end of outer section 2l. The outer seotion moves only o eut oli the supply of air 'to the working parts of the hammer as above set forth. The rearward 'movement of this outer section is limited by the engagement of the rear end of the valve section with the head 5 and the forward movement by the engagement of the forward end of the outer section with the flange 23.

It will he noted that my improvements prevent accidental removal of the tool or piston. In the event the bushing is forced backward by accident, sufficient to admit motive fluid to the valve. a sharp blow will be delivered against the oiiendingr objet-t, but there will be no displacement of the tool. I would also have it understood that the ring 53 and lguard 35 are not intended to be complete circles. This permits the guard ring to he turned to direct the exhaust Wherever desired, and both parts can be readily inserted in position or removed from the hammer.

Various slight changes might be made in the general form and arrangement of parts described without departing from my invention, and hence I do not limit myself to the precise details set forth. but consider lnvself at liberty to make such changes and alterations as fairly fall Within the spirit and scope of the appended claims.

Having thus described my invention, what I claimas new and desire to secure by Letters Patent is:

1. In a pneumatic hammer, the combination with a barrel, a valve in one end of the barrel, a longitudinally movable tool-sup- `Ward position of the bushing,

nieuwe l'uuting luishiug in the olher ond of the harA rel. and said bushing adapted to dirent live liuid against the valve to shut oll the iuh-t pt' fluid to the hauuner phen the lsushiug is in its :lute:- posiiiou. sulyataniailv as sl'rilail. M

2. ln a pneuluatir` hsuuuier, the combination With a barrel. a valve in one. end ol' the barrel, a longitudinally niovahh; toolalup porting luishing in the other ond of the bar4 rel. and said bushingf :'u'laiited to .lii'elyi live iiuid aauiusi lluvalve 1o shut di liu inlet `olA lluid do lluhzuuuuu' when the hashing' is ils itsloutr-l p 'tuin :lud :i spring; noiuially uur said luishinz outuardlv. substanas di rrihed. l

minutie hammer, the m'nullilm. tion wiah a irrol. a valve in nuo end ui' 'ilu hrw-rel. a fitudiually movable tools\ip portionl bushiu? in the other end of the har rel. and said bushing adapted to divert live tluid against the valve to shut oil the inlet of iiuid to the hammer when the bushing is in its outer position. said bushing having an annular shoulder against. which live fluid is direeted during the outvvard position of the bushing. suhstauti; llv as deseriliied.

Si. lu a pueumutio hammer. the oouiliination Vwith a hai-rel. a TJive iu one oud of the barrel, a longitudinally movable tool-supportingr luishing in the other end ot' the barrel. `aud said bushingr adapted to direet live vfluid against the valve to shut oil the inlet of fluid to the hammer when the bushing is in its outer position, a spring; normally uros-dug said bushingouivardlv. said bushingr having au annular shoulder against u'hirh live fluid is direi-ted during1 the outward position oi` the bushing, substantially as described.

In a pneumatic hammer, the Combination with a barrel. a valve in one end of the barrel. f. loiuritiulinally movable tool-supporting' bushing in the other end of the barrel. and said bushing adapted to direct live fluid against the valve to shut off the inlet of fluid to the hammer when the bushing is in its outer position, said bushing having an annular shoulder against which live fluid is directed during the outward position of the bushing, said fluid pressure against the bushing out off by the inward movement of the bushing, substantially as described.

6. In a pneumatic hammer, the combination with a barrel. a valve in one end of the barrel, a longitudinally movable tool-supporting bushing in the other end of the barrel. and said bushing adapted to direct live fluid against the valve to shut olf the inlet of fluid to the hammer When the bushing is in its outer position, a spring normally pressing said bushing outwardly, said bushing having an annular shoulder against which live fluid is directed during the outsaid fluid to entirely cut pressure' against the bushing being cut off, y the inward movement of the bushing, substantially as described.

7. In a pneumatic hammer, the combination with a barrel, a valve in the rear end of the barrel, of a longitudinally movable tool supporting bushing in the forward end of `the barrel, a coiled spring around the bushvmission of fluid tothe hammer when the bushing Lis 'in its outward position, substantially as described.

8. In a pneumatic hammer, the combinationl with a barrel, of a reciprocating valve in the rear end ofthe barrel controlling the movement of the piston, a tool sup orting bushing longitudinally movable in the for- Ward end of the barrel, and said bushing vconstructed to control the flow of fluid to one pressure surface of the valve to move the `valve to closed position when the bushing is in its forward position, substantially as described.

9. Ina pneumatic hammer, the combinationwith a barrel, of a reciprocating valve in the rear end of the barrel controlling the movement of the piston, a tool supporting bushing longitudinally movable in the forward end of the barrel, and said bushing constructed to control the flow of fluid to one pressure surface of the valve to move the valve to closed position when the bushing is in its forward position, and said bushing constructed to expose said pressure surface tothe atmosphere when the bushing moved inwardly by pressure of the tool against the work, substantially as described.

10. In a pneumatic hammer, the combination with a barrel, of a valve located in the rear end of the barrel, a piston in the barrel, said barrel havin passages and ports therein controlled by t e valve, whereby the piston is caused to reciprocate in the barrel, a tool-holding bushing movable longitudinally in the forward end of the barrel, said bushing when pressed inwardly adapted to connect passages in the barrel, whereby live fluit: ressure ,is directed against the valve oil' supply of fluid to the hammer, substantially as described.

11. In a pneumatic hammer, the combination with a barrel, a valve in one end of the barrel, a longitudinally movable` tool-supportingbusliing in the-other end of the barrel, and saidbushin adaptedto directlive lluid again-st the va ve to shut 0H the` inlet of fluid to the hammer when the bushm 1s two sections, one section lciprocated by the normal inlet of fluid to coi-.trol the olieratioi. of the piston, and the other section movable by the fluid as controlled by the bushing to sluit off the flow of fluid when the bushing is in its forward position, substantially as described.

12. In a pneumatic hammer, the combination with a barrel, a valve in one end of the barrel, a longitudinally movable tool-supporting bushing in the other end of the barrel, and said bushing adapted to direct live fluid against the valve to shut off the inlet of fluid to the hammer when the bushing is in 1ts outer position, a spring normally pressing said bushing outwardly, said valve composed of two sections, one section reciprocated by the normal inlet of fluid to control the operation of the piston, and the other section movable by the fluid as controlled by the bushing to shut off the flow of fluid when the bushing is in its forward position, substantially as described.

13. In a pneumatic hammer, the combination with a barrel, a valve in one end of the `barrel, a longitudinally movable' tool-supporting bushing inthe other end of the barrel, and said bushing adapted to direct live iluid against the valve to shut off the inlet of fluid to the hammer when the bushing is in its outer position, said bushingr having an annular shoulder against which live iluid is directed during the outward position of the bushing, said valve composed of two sections, one section reciprocated by the normal inlet of fluid to control the operation of the piston, and the other section movable by the fluid as controlled by the bushing to shut ofll the flow of fluid when the bushing: is in its forward position, substantially as described.

la. In a pneumatic hammer, the combination with a barrel, a valve in one end of the limrrel, a longitudinally movable tool-supporting bushing in the other end of the barrel, and said fluid against the valve to shut olf the inlet of fluid to the hammer when the bushing is in its outer position, a spring normally pressing said. bushing outwardly, said bushing having an annular shoulder against which live fluid is directed during the outward position of the bushing, said valve composed of two sections, one section reciprocated by the normal inlet of fluid to control the operation of the piston, and the other section movable bythe fluid as controlled by the bushing to vshut oil' the flow of fluid when the bushing is in its forward position, substantially as described.

15. In a pneumatic hammer, the combination with a barrel, a valve in one end of the theuother end o'f the barrel and said bushin in its outer position, said valve compose of t fluidl against the va ve to shut off the inlet bushing adapted to direct live barrel, a` longitudinally movable tool-sup-` ,ILO

lui

of fluid to the hammer when the bushing is in its outer position, said bushing having an annular shoulder against which live fluid is directed during the outward position of the bushing, said fluid pressure against the busliing cut off by the inward movement of the bushing, said valve composed of two sections, one si, 4tion reciprocatcd by the normal inlet of Huid to control the operation of the piston, and tbe other section movable by the fluid as ccntrolledby the bushing to shut oli' the flow of fluid when the bushing is in its forward position, substantially as described.

lll. ln a pneumatic hammer, the combination with a barrel.r a valve in one end of the barrel, a` longitudinally movable toolsupporting bushing .in the other end of tbc barrel. and said bushing adapted to direct live fluid against the valve to shut off the inlet of iluiil to the liammer when the hush ine` is in its outer i'iosition, a spring normallv p .said bushing outwardly. said liualling; in ing an annular shoulder against which lfY lluifl directed during:` tbc outirai-d punition of tile lau-airing, said fluid pressure against the bushing cut olf by the inward movenient of tile bushing. said valve wiapowl ol' tivo sections. one section recipromterl by flic normal inlet of lluid to coni'wl the .yprration of thrpiston. and tlic naovail. by he fluid iig-,1 conV fishiwg to s n 'l the flow '1 'foru'alil ve in tlio ,v4-ar .end iuilinally mov lr" rupiiufinf; i ,j in the fiaivarl end larnl. :i rollt-rl ,spring around the eue-ting"outward pressa-fe there b veel lmvirgf a pre y for livr` "wl pii-. i1w w flic lnslr isili its outward posiiptcd to out oli" said ,i Ll inurl-illy. and said fu liront ille livr llllii'l, #uiuc L iiultft inc valve to sluit or. of 'lluii'l to tlie hammer l lid i avril. ol

* is il its outivarrl position. I'. valvicomposcd of two .sentions.` onf; stil-'n rt-cipri *ed by Llie normal inlet l fluid ro ronlrol ille operation of the piston, :nil the other ser'rtion movable by the fluid as controlled by ille bushing to shut ofi' tbe flow of fluid )vlieo tlm bushing` is in its forward position, substantially as described..

1S. In a pneumatic hammer, the combination with a barrel, `of a reciprocating valve in the rear end of the barrel controlling the movement of the. piston, a tool supporting bushing longitudinally movable in the forward end of the barrel, and said bushing constructed to control the flow of `Huid to one pressure surfaceof the valve to move the valve to closed position whenv the bushing is in its forward position, said valve composed of two sections, one section reciprocated by the normal inlet of fluid to control the operation of the piston, and the other section movable by the fluid as controlled by the bushing to shut ofl the flow of fluid when the bushing:r is in its forward position, substantially as described.

19. 1n a pneumatic hammer, the combination with a barrel, of a reciprocating valve in the rear end of the barrel contreling the movement of the piston, a tool supporting bushing longitudinall)T movable in the forward end of the barrel, and said bushing constructed to control the flow of fluid to one pressure surface of the valve to move the valve to closed position when the bushing is in its forward position, and said lmsliingY constructed to expose said pressure surface to tbe atnu'iapliere when the bushing is moved inwardly by pressure of the tool against a rivet.y said valve composed of tivo sections. one section rcciprorated by the normal. inlet of fluid to control lthe operation of the piston. and the other bro-rift said barrel having passages and puts tous controlli-il by the valve. Wherely'f ille o tu'. i caused to ivrwrocate in tbe -vtziirl u toolliohling lutsl a: movable lon- `uitiuliiuallg io the forward, ual oi' the barrelV :will lulfzliinz'; when pressed inwardly adapted to connect passages in tbe barrel, wherein.' live fluid pres-lauro directed against the valve` to entirely cut ofl supply of lluid to the hammer, said valve composed ol' two sections. one section reciprocated by tbe normal inlet of fluid to control the operation of the piston, and the other section movable by tbc fluid as controlled by the lurfliincV to sluit oli' the flou" of fluid when thv4 husliino is in its forivare'l position, subsfantial as described.

2l. l'n a pneumatic hammer the combination With a barrel, a valve in one end of the barrel, a longitudinally movable toolsupporting bushing in the other, end ol the barrel, and said bushingr adapted to direct live .fluid against the valve to shut off the inlet of fluid to the hammer when the busliing is in its outer iosition. said valve composed of two cylindrical telescoping sections, the outer section movable longitudinally to shut off fluid to the inner section, said movement controlled by the bushing, andthe inner section movable longitudinelly by the fluid to control the movement of the piston, substantially as described. A

22. In a pneumatic hammer, the combination with a barrel, a valve in one end of the barrel, a longitudinally movable tool-supl porting bushing in the other end of the barrel, and said bushing adapted to direct live fluid against,the valve `to shut ofi' the inlet of fluid to the hammer When the bushing is in its outer position, a spring normally pressing said bushing outwardly, said valve romposed of two cylindrical telescoping seclions,` the outer section movable longitudinally to sluit off fluid to the inner section, said movement controlled by the bushing, and the inner section movable longitudinally by the fluid to .control the movement of the piston substantially as described.

Q3. 4n a pneumatic hammer, the combination with a. barrel, a valve in one end of the barrel, a longitudinally movable toolsupporting bushing in the other end of the barrel, and said bushing adapted to direct live fluid against the valve to shut oil the inlet of fluid to the hammer when the bush ing is in its outer position, said bushing having an annular shoulder against which live fluid is directed during the outward po' sition of the bushing said valve composed et' two cylindrical telescoping sections, the outer section movable longitudinally to shut ofi" f luid to the inner section, said m'ovement controlled by the bushing, and the inner section movable longitudinally by the fluid to control the movement of the piston, Substantially as described.

Eil. ln a pneumatic hammer, the combinafion with a barrel, a valve in one end of the barrel, a longitudinally movable tool-sup.- porting bushing inthe other end of the barrel, and said bushing adapted to direct live fluid against the valve to shut off the inlet of' fluid to the hammer when the lbushing is in its outer position,' a spring normally pressing said bushing outwardly, said bushing having an annular shoulder against which live fluid is directed during the outward position of the bushing, said valve composed of two cylindrical telescoping sections, the outer section movable longitudinally to shut ofi1 fluid to the inner section, said movement controlled by the bushing, and the inner section movable longitudinally by the fluid to control the movement of the piston, substantially as described.

25. In a pneumatic hammer, the combination with a barrel, a valve in one end of the barrel, a longitudinally movable toolsimporting bushing in the other end of the barrel, and said bushing adapted to direct live fluid against the valve to shut off the inlet of fluid to thehammer when the bushing is in its outer position, said bushing having an annular shoulderagamst which live fluid isdirected during the outward position of the bushing, said fluid pressure against the bushing cut` ofi: by the inwardmovementof-the bushing, said valve 4composed of two cylindrical telescoping secthe barrel, a longitudimllly movable toolsupporting bushing in the other end of' the barrel, and said bushing adapted to direct live fluid against the valve to shut oil' the inlet of fluid to the hammer when the bushing is in its outer position, a spring nor-= mally pressing said bushing ol-ltwardly, said bushing having an annular shoulder againsl which live fluid is directed during the oulward position of the bushing, said fluid pressure against the bushing cut ofil by the inward movement of the bushing, said valve composed of two cylindrical telescoping sections, the outer section movable longitudinally to shutolf fluid to the inner section, said movement controlled by the bushing, and the inner section movable longitudinally by the fluid to control the movement of' the piston, substantially as described.

2. In a pneumatic hammer, the combination with a barrel, a valve in the rear end of the barrehiof a longitudinally movable tool supporting bushing in 4the forward end of the barrel, a coiled spring around the bushing exerting outward pressure thereon, said barrel having a passage` for live fluid exertilw outward pressure on the bushing when elle latter is in its oufward'position, said'bushing adapted to eut ofi' said live fluid when moved inwardly, ing coi'istructed to direct the live fluid from saidfpassage against the valve to shut off the admission of fluid to the hammer when the bushing is in its outward position, said` valve composed of two cylindrical telescoping sections, the outer section movable longitudinally to shut off fluid to the inner section, said movement controlled by the bushing, and the inner section movable longitudinally by the fluid to control the inove'- nient of the piston, substantially as described.

28. In a pneumatic hammer, the combination wi l1 a barrelv` of a reciprocating valve in the rear end of the barrel controlling the 'movement of the piston, a tool supporting bushing longitudinally movable in the forward end of the barrel, and said bushing constructed to control the flow of fluid to one pressure surface of the valve to move the valve to closed position when the bushing is in its forward position, said valve composed of two cylindrical tclescoping sections, the outer section movable longitudinally to shut Oil' fluid to the inner section, said movement controlled by the bushi; g, and the innersecmovable longitudinally and said bushtion movable longitudinally by the iluid to control the movement of the piston, substantially as described.

29. In a. pneumatic hammer, `the combination with a. barrel, of a reciprocating valve in the rear end of the barrel controlling the movement of the piston,` a tool supporting bushing longitudinallyY movable in the forward end of the barrel, and said bushing constructed to control the flew of fluid to one pressure surface of the valve to move the valve to closed position when the bushing is in its forward position, and said bushing constructed to expose said pressure surface to the atmosphere when the bushing is moved inwardly by pressure of the tool against a rivet, said valve composed of tvvo cylindrical telescoping sections, the outer section movable longitudinally to shut eti Huid to the inner section, said movement controlled by the bushing` and the inner section movable longitudinally by the tiuid to control the -movement of the piston, substantially as described. p

30. In a pneumatic hammer, the combination with a barrel, of a valve located in the rear end of the barrel, a piston in the barrel, said barrel having passages and ports therein controlled by the valve, whereby the piston is caused. to reciprocate in the barrel, a tool-holding bushing movable longitudinally in the forward end of the barrel, said busliing when pressed inwardly adapted to connect passages in the barrel. whereby live fluid pressure is directed against the valve to entirely cut ol supply of fluid to the hainmer, said valve composed of two cylindrical telescoping sections, the outer section mow able longitudinally to shut olf fluid to the inner sectien,said movement controlled by the bushing, and the inner section movable longitudinally by the fluid to control the movement of the piston, substantially as described.

31. In a pneumatic hammer, the combination with a barrel, a valve in one end of the barrel, a longitudinally movable toolsup porting bushing in the other end of the barrel, and said bushing adapted to direct live fluid against the valve tosliut oil the 'inlet of fluid to the hammer when the bushing is in its outer position, said barrel having an internal longitudinal groove communicating at one end with an internal annular groove, the latter having a longitudinal entrance groove, and said` bushing having a key adapted to enter through the last-mentioned groove, turned in the annular groove, and

Y positioned in the longitudinal groove, Whereby the movement of the bushing is limited in both directions, substantially as described.

32. In a pneumatic hammer, the combination ivith a barrel` a valve in one end of the barrel, a longitudinally movable tool-supporting bushing in the other end of the barrel, said bushing adapted to direct live fluid against the valve to shut olf the inlet of Huid to the hammer when the bushing is in its outer posit-ion, and means exertingacontinuous outwardpressure on the bushing, substantially as described.

33. ln a pneumatic hammer, th'e combination with a barrel, a valve in one end of the barrel, a longitudinally movable tool-supporting bushing in the other end of the barrel, said bushing adapted to direct live fluid against the valve to shut 0H the inlet of fluid to the hammer when the bushing is 4in its outer position. and a coiled springaround the outside of the bushing exerting a continuous outward pressure ou the bushing, substantially as described,

ln testimony whereof l have signed in v name to this specification in the presence ol tivo subscribing witnesses.

GEORGE LAWSON ROBERTSON.

Witnesses:

M. E. DirrUs, Unas. E. Porre.

rectlon in Letters Patent No. 1,167,550.

tion movable longitudinally by the fluid to i tially as'dcscribed.

29. In a pneumatic hammer, .the combination with a barrel, of a reciprocating valve in the rear end of the barrel Controlling the movement ot' the piston., a tool supporting bushing longitudinally movable in the forward end of the barrel, and said bushing constructed to ycontrol the flow' of fluid to one ressure surface of thev valve to move the valve to closed position when the bushing is'in its 'forward position, and said bushing constructed to expose said pressure surface to the atmosphere when the bushing is moved inwardly by pressure of the tool against a rivet, said valve composed of two cylindricalftelescoping sections, the outer section movable longitudinally to shut oil fluid to the "inner'section, said movement controlled by the bushing, and the inner section movable longitudinally bythe fluid to control the movement of the piston, subcontrolthe movement of the piston, substanstantially as described p 30. In a pneumatic hammer, the con'ibination with a barrel, of a valve located in the rear end of the barrel, a piston in the barrel, said barrel having passages and ports there` .in controlled bythe valve, whereby the piston is caused. to reciprocate in the barrel, a tool-holding bushing movable longitudinally in the forward end of the barrel, said `liiushing. when pressed inwardlyadapted to conneet lpassages in the barrel.` whereby live fluid pressure is directed against the va ve to entirely cnt oll' supply of fluid to the hammer, said valve composed ot two cylindrical. telescoping sec ions, the outer section inovable longitudinally to shut off .duid to the inner section, said movement controlled by the bushing, and the inner section movable longitudinally by the fluid to control the movement of the piston, substantially scribed.

31. In a pneumatic hammer, the combinaas' defor an improvement in Pneumatic Hammers,7 an error appears in the printed tion with a barrel, a valve in one end of the barrel, a longitudinally movable tool-supporting bushnigin the other end of the barrel, and said bushing adapted to direct live 4 iluid against the valve to shut oil the 'inlet of fluid to the hammer when 'the bushing i in its outer position, said barrel having an internal longitudinal groove communicating at one end with aninternal annular groove, the latter having a longitudinal entrance groove, and said bushing having a key adapted to enter through the last-mentioned groove, turned in the annular groove, and groove, where-y positioned in the longitudinal by the movement of the bushing is limited in both directions, substantially as described.

32. In a pneumatic hammer, the combination with a barrel, a valve in one end of the barrel, a longitudinally movable tool-supporting bushing in the other end of the oarrel, said bushing adapted to direct live fluid `against the valve to shut off the inlet of duid to the hammer when the bushingv is Vin its outer position, and a coiled spring around the outside of the bushing exerting a continuous outward 'pressure on the bushing,-

substantially as described.

In testimony whereof I have signed my name to` this specification in the presence ot two subscribing witnesses.

GEORGE LAWSON ROBERTSO.

lVitnesses:

M. E. DirrUs, CHAS. E. Po'rrs.

It is hereby certified that in Letters Patent N o. 1,107,550, granted August 18, 1914,

specification requiring ycorrection as follows: Page 5, line 53, for the Word inwardly` read forwardly," and that .the'said Letters Patent should be read with this correction therein that the same may conform to the` record of the case in the Patent Signed and sealed this 22nd day of September, A. D., 1914.

R.F. WHITEHEAD, Aer/ng ommz'saoner of Patents.

Correction inLetters'Patent No. 1.107.550.

Ic is herebycer'tiad 11min Letters Patent No. 1,1o7,-55o,g1aued August 18, 1914,

for un improvement in Pneumatic Hammers, an f'rx'ol appears in nho printed` peca'iiion -requring correction as follows: Page 5, line 53, for the word nvarldnlyrre1id forwardly," and` that .tho said Letters `Paten-t shouvld be reod withthis oorrectiontheiein that the same may conform to the4 record of the case the Patent Signed 'and soaled th s`22nd day of Seftember, A. D., 1914.

[SEAL] 4 Aczang ,Commissioner ofPatmts. 

